1. Field of the Invention
This invention relates to friction reducing additives for lubricants and liquid fuels. More particularly, the invention relates to lubricant and fuel compositions to which has been added a borated phosphorus- and nitrogen-containing compound.
2. Discussion of the Prior Art
The metal surfaces of machinery or engines operating under heavy or normal loads wherein metal is under friction, undergo metal to metal contact even when being lubricated. Thus, there is always metal wear which can be excessive. Often lubricants used to protect the metal surfaces do not completely prevent wear at the points of metal to metal contact. Consequently, the performance of the machine or engine will suffer, and in aggravated cases the machine or engine may become completely inoperative from excessive wear caused the friction.
There have been many attempts to devise additive systems to improve the friction properties of a lubricant. The phosphate derivatives of the present invention are believed to be capable of overcoming some of the deficiencies of prior art additives and to provide lubricating oil compositions with enhanced friction characteristics.
U.S. Pat. No. 2,758,971 describes a class of metal phosphonates which are disclosed as having properties which prevent breakdown of oils at high temperatures.
U.S. Pat. No. 2,792,374 discloses the alkali metal salts of certain alkyl alkylphosphonic acids as defoamants in aqueous systems.
U.S. Pat. No. 4,356,097 teaches an engine crankcase lubricating oil containing a dihydrocarbyl hydrocarbylphosphonate, which oil exhibits reduced friction.
U.S. Pat. No. 2,982,727 discloses lubricating oil compositions containing certain salts of oxygen-containing esters of phosphorus. The esters are phosphonates similar to those described in U.S. Pat. No. 2,758,971.
U.S. Pat. No. 4,382,035 discloses a new glycerol-3-phosphoric acid halogenalkyl ester of the formula ##STR1## where R, R', X and y are as defined therein. Certain diols have been disclosed as having lubricity properties when formulated into lubricants and for their water-scavaging abilities in fuels. Phosphate esters are well known as functional lubricants.
The use of boron containing compositions has also been widely reported. Borates and borate esters are disclosed in U.S. Pat. Nos. 4,370,248; 4,298,486 and 4,273,665.
Many phosphorus containing additives have found widespread use in the past. Phosphonates have been used as lubricity agents as exemplified by Papay in U.S. Pat. No. 4,356,097 in his disclosure of dihydrocarbyl hydrocarbyl phosphonate containing lubricant compositions.
Certain long chain vicinal diols are disclosed in U.S. Pat. Nos. 3,649,358 and 3,899,433.
Amines and amine borate compositions have been used as friction modifying additives, as exemplified in U.S. Pat. No. 4,328,113.
However, no art is known that teaches or suggests the phosphate ester of the present invention.
The use of the novel borates of diol-derived partial phosphate esters in lubricants provide effective multifunctional friction reducing, antioxidant, antiwear and copper passivating activity, with potential antifatigue and grease high temperature stabilizing properties.